1. Field of the Invention
This invention relates to container bags and in particular relates to container bags for carrying loads in the range of one half to two tons and known as flexible intermediate bulk containers (FIBC's).
2. Description of Related Art
Flexible intermediate bulk containers are increasingly employed in cargo handling and transporting situations, especially for the carriage of particulate or pulverulent material. A typical FIBC will be manufactured from a fabric woven from a polyolefin tape and have integral lifting loops. Examples of such containers are described in UK patent numbers 1591091 and 2063816. FIBC's have to meet various national and international safety standards; for example, it is normal to require a five to one safety ratio, that is an IBC rated at one ton should not break under loads of less than five tons.
A recent trend in the FIBC field has been the increasing usage of FIBC's having a much squarer configuration for powdered, flaked or granular materials which do not form a stable package when filled into an FIBC. Examples include products with a low specific gravity. Other products tend to pack more firmly in a square cross-section. The square configuration also improves the packing of filled FIBC's in, for example, ISO containers, as well as improving stacking.
One proposal for obtaining an FIBC more square in plan view involves sewing baffles across the internal corners to hold the square shape. The baffles have holes in them to allow the product to flow into the corners. However, the provision of baffles of the required configuration and, in particular the extra sewing required, increases the cost of manufacture of these bags.
The invention seeks to provide a container bag improved in the above respect.